I came across a problem with the application Neutron musuc player (http://neutronmp.com).
After purchasing the application and insatlling Neutron it inspects system for license by requests a list of POP3 / IMAP accounts and settings from the operating system tries to find for each of its remote license database (purchase). If it is found - registration successful. I have a Google account active, but check оf the license by application does not pass. Аpplication developer sais that in Sailfish can be some restrictions or the ability to cancel the permission to android app get acoount settings from operating system.
So the question is - can it be true and how it can be solved?
PS: Neuron seems to be the best music player between all OS I've used before, but after 5 days of trial it becomes blocked.

Here is the answer from the Neutron developer (translated from Russian):
"We plan to port to that platform, but we are still waiting, because Sailfish have not yet decided about the paid apps. Alternatively, the neutron can be sold through PayPro, because It is a universal, platform-independent solution, unless Sailfish will make it possible to receive read permissons of mail accanut similar to the Android OS. Also a problem is the uncertainty in the fate of the platform (mean Sailfish OS)."
So lets cross fingers and wait.